Alloy for soft magnetic layer in perpendicular magnetic recording medium

Abstract

A soft magnetic alloy for perpendicular magnetic recording medium excellent in saturation magnetic flux density, amorphousness and atmospheric corrosion resistance. The alloy is an Fe—Co based alloy and comprises Fe in an amount satisfying 0.25 to 0.65 of Fe/(Fe+Co) ratio, which is an atomic ratio of Fe and Fe+Co; Zr+Hf in an amount of 6 to 100 at %; Na+Ta in an amount of 0 to 2 at %; Al and/or Cr in an amount of 0 to 5 at %; and the balance Co and unavoidable impurities. A part of Zr and/or Hf can be replaced by B, provided that the amount of B to replace Zr and/or Hf is double in at % of the total amount of Zr and Hf to be replaced and that the total amount of Zr and Hf after replacement is 4 at % or more.

1. An alloy for a soft magnetic layer in a perpendicular magnetic recording medium, the alloy being an Fe—Co based alloy and consisting essentially of:
 Fe: an amount satisfying 0.25 to 0.65 of Fe/(Fe+Co) ratio, which is an atomic ratio of Fe and Fe+Co; 
 Zr: 6 to 11 at %; 
 Nb+Ta: 0 to 2 at %; 
 Al and/or Cr: 0 to 5 at %; and 
 balance Co and unavoidable impurities. 
 
     
     
       2. The alloy according to  claim 1 , wherein a part of Zr is replaced by B, provided that the amount of B to replace Zr is double in at % of the amount of Zr to be replaced and that the amount of Zr after replacement is 4 at % or more.